Dan Parks steered Connacht to a famous 22-14 victory over French giants Biarritz at the Sportsground on Friday night.

Parks kicked 17 points, including the conversion of Fetu'u Vainikolo's early try, to seal the province's second win in Pool 3 that keeps their quarter-final hopes alive. Dimitri Yachvili kicked three penalties to leave the visitors 10-9 behind at the break, but Biarritz were decidedly brittle as Connacht's younger forwards outworked them. Although Imanol Harinordoquy came off the bench to score an injury-time try, Yachvili missed the conversion for a losing bonus point.

It was a tremendous result for Eric Elwood's men, with Parks guiding a hard-running back-line and Mike McCarthy marshalling the young guns up front. With Gavin Duffy, John Muldoon and Nathan White heading the province's 13-man injury list, Parks skippered Connacht and varied the play superbly early on.

After Yachvili nudged Biarritz ahead, Vainikolo struck for a superbly-taken try that really lifted his team-mates and the vocal home crowd. David McSharry intercepted a pass from Charles Gimenez near halfway and offloaded for the Tongan winger to charge away for a score against the run of play. Parks converted to put Connacht 7-3 ahead and the westerners missed out on a second try when Ireland lock McCarthy failed to spot Robbie Henshaw looping around him in plenty of space.

A series of penalties failed to budge the scoreline with the wind-backed Yachvili missing two shots at the posts, and Parks drifting a long-range attempt wide. The Biarritz talisman was back on target at the midway point of the half, his second successful penalty following a decent bout of territory for the visitors.

Connacht looked the more dangerous of the two sides off limited ball and Takudzwa Ngwenya had to concede a lineout as Tiernan O'Halloran chased hard. The hosts pressed and Parks took the drop-goal option, in front of the posts, to reopen the four-point gap.

Biarritz looked lacklustre in thought and deed, and tigerish tackling from the likes of Willie Faloon, Michael Kearney and Eoin McKeon helped Connacht keep their defensive line intact. However, the penalty count took its toll. Number eight McKeon was sin-binned for taking an airborne Iain Balshaw out and Yachvili snapped over a classy penalty to make it 10-9 at the interval.

Despite their greater experience and strength up front, Biarritz failed to hammer home their numerical advantage and Parks restarted the scoring in the second period with a penalty.

Connacht countered again moments later, tournament debutant Danie Poolman punching down towards the 22. Parks hung up a cross-field kick which O'Halloran was inches away from collecting. Biarritz introduced the fit-again Harinordoquy as they tried to reassert themselves, but strong carries from McSharry and Henshaw preceded another Parks three-pointer.

Parks and company kicked cleverly to keep Biarritz pinned back and McCarthy and hooker Jason Harris-Wright kept the home forwards on the front foot. They forced a scrum penalty that Parks missed to the right, yet further chances came and in the final 10 minutes the former Scotland fly-half landed an inspirational drop goal and a third and final penalty.

Biarritz's game descended into niggly phases, with their questionable attitude and temperament resulting in a couple of scraps between the forwards. They did lift the tempo late on, powerhouse Harinordoquy piling over after O'Halloran was sin-binned during some desperate Connacht defence. But Connacht deservedly failed to cough up the losing bonus point and they will head to south-west France for next week's return encounter with renewed confidence.

For Connacht coach and former captain Eric Elwood, who is leaving the province at the end of the season, picked out the young charges that he threw into the fray after a number of seniors players were ruled out with injury and helped the team to only their third ever Heineken Cup victory.

"It is a huge scalp for us," he said. "Biarritz had a full squad out there tonight and we had a lot of guys missing," he said, referring to a Connacht injury list that includes Michael Swift, regular captain Gavin Duffy, John Muldoon, Nathan White, Frank Murphy and George Naoupu.

"A lot of credit must go our young guys, particularly in the forward pack. The platform from our forward pack was terrific. To get scrum penalties against Biarritz was magnificent and Dan (Parks) kept the scoreboard ticking over, so all in all it was great. Thankfully it finished in our favour and they got nothing out of the game. That is a good feeling, it would have been awful if they had got a bonus point [with the conversion] at the end."

The defeat came as a big shock to the winners of last year's Amlin Challenge Cup and a club that has twice reached the final of the Heineken Cup. They will now have to quickly find for ahead of the return fixture in the Basque country next weekend. They are still capable of reaching the knockout stages, but the defeat has meant that they will now need to be at their very best to do so.

"It is bitterly disappointing," fullback Iain Balshaw said. "Mathematically there is a chance we can qualify, but it will be very tough. Presumably we will need to get five points from every match here in. I don't know how many turnovers we made, probably three times as many as Connacht and at this level you cannot win rugby matches [playing like that], not just in the Heineken Cup but in the Top 14," he said. "Unfortunately, we just do not have the consistency at the moment."